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(No Model.) 2 Sheets-Sheet 1..

A. NORMAND. STEAM ENGINE ATTACHMENT.

Patented Feb. 6, 1894.

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Patented Feb. 6,. 1394.

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AUGUSTIN NORMAND, 0F HAVRE, FRANCE.

STEAM-ENGINE ATTACHMENT.

.SPECIFGATION forming part of Letters Patent No. 514,333, dated February6, 1894.

Applicationiiled September 5,1893. Serinlll'o. 484,861. -tNo model.)Patented in France July 29, 1887, No. 185,071; in England July 29, 1887,No.10,545, and in Belgium September 3,1889,No. 87,605.

To @ZZ whom it may concern/.-

Be it known that I, AUGUSTIN NORMAND, a citizen of France, and aresident of Havre, in the Department of the Seine-Infrieure, France,have invented a new and useful Improvement in Steam-Engine Attachments,(for which I have obtained patents in France, No. 185,071, dated July29, 1887; in Great Britain, No. 10,545, dated July 29, 1887, and inBelgium, No; 87,665, dated September 3, 1889,) of which the following isa specification.

The compression of the steam at the end of the stroke of the pistonpresents the advantages, as is well known, of neutralizing entirely orpartially the prejudicial influence of clearance and of heating thesurfaces of the cylinder which come in contact with the entering steamand also of enabling the engine to runat high speeds which wouldotherwise When the exhaust and admission of steam are controlled by asingle valve it appears impossible, with the arrangements ordinarilyemployed, 'to vary the expansion without producing corresponding changesin the compression. Consequently the compression cannot be regulatedproperly for all conditions of expansion. When the Stephenson linkmotion, or other analogous arrangements are employed the degree ofcompression increases rapidly with the ratio of expansion, and even whena special or separate slide valve is employed for the exhaust, there isalways a risk of the slide being slightly out of order andfwhen thisoccurs the compression may become excessive so that the pressure of thesteam in the cylinders is liable to rise much higher than that in thevalve chest. This is especially the case with the high pressure nowused, where a few degrees of superheating will prevent steam fromcondensing without a large increase of pressure.

In order to provide against this danger and obtain from compression allthe advantages that it presents in theory, and render it independent ofthe ratio of expansion, the cylinders of steam engines constructedaccording to this invention are provided with safety valves so arrangedas to blow off into the valve chestinstead of into the open air. Thisrenders it impossible for the pressure within the cylinder ever togreatly exceed that in the valve chest and the steam being blown ed intothe valve chest is not wasted. The loss of power resulting from thisarrangement is little er none, as the opening of exhaust is delayed, andin any case the portion of the curve of the indicator lost by thecompression when the engine is working with great expansion, correspondswith the end of the stroke where the useful effect produced upon thecrank shaft is almost ml. The safety valves are pressed to their seatsby the pressure existing within the slide valve chest so that anVextremely slight spring is sufficient to insure perfect contact with theseats, and a prompt closure directly the excess of pressure which hasopened or lifted, the valve is removed. Moreover the period of timeavailable for closing the valve is always sufficient even when theengine is running at a high speed, as it is equal to that comprisedbetween the admission and the cut off of steam.

Valves which are almost noiseless in-their action are now employed inair pumps, and it is evident that the same or analogous arrangements maybe employed in the present case with like results. Moreover there is notthe same tendency to produce a loud noise as there is with ordinaryvalves which require to be heavily loaded. By making the joint of thevalve with lead or other but slightly elastic substancea noiselessaction can beinsured. Slide valves arranged to lift slightly in case ofan excess of pressure inthe interior of the cylinder could'not beemployed with the same effect, as the rubbing surfaces would wear outrapidly, and the noise produced would be objectionable. These new valvesenable the ordinary safety or blow off valves of the cylinders to bedispensed with. They suffice to let off any water that may accumulate inthe cylinders, a single blow off cock being placed on the valve chest.

Figure l of the accompanying drawings represents a section of a part ofa steam engine constructed according to this'invention, the sectionbeing taken along the line I J, Fig. 2. Fig. 2 is a section taken alongthe line K L, Fig. 3, and Fig. 3 is a section taken along the line M N,Fig. 2. Fig. 4 represents one of the blow off valves in a section takenalong the line O l? Figl 3.

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one hand with the interior of the cylindery through passages E E Figs. land 2, and open directly into the steam chest on the other hand asindicated in the drawings.

Having now particularly described and ascertained the nature of the saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is- The combination with an engine cylinder having a valvechest, supply passages B for the cylinder, and an exhaust C, ofindependent blow-0E valves arranged respectively at opposite endportions of the cylinder and communicating by passages E, which areindependent'of the passages B, with the cyllnder, said valves beingunseated by pressure in the cylinder and blowing o into the valvechest,substantially as and for the purposes described.

In testimony whereof I have signed this specification in the presence oftwo subscribing witnesses.

AUGUSTIN NORMAND. Witnesses:

C. B. PIKE, G. OARTING.

